Rotary material cutting or milling devices—such as road pavement mills, surface mining machines, or rotary cutter attachments for hydraulic excavators or the like for example—utilize replaceable cutting tools or bits to cut and remove material from a surface. Typically, the cutting tools wear out quickly and are thus replaced frequently and, in heaving cutting or milling operations, cutting tool replacement may be carried out daily. In some cutting or milling devices, the cutting tool is removably mounted in a tool holder that is itself removable mounted to a rotary drum. In such devices, the tool holder also wears out and is replaced, although typically not as frequently as the cutting tool.
Because rotary cutting or milling devices typically carry a large number of cutting tools, ease of tool and tool holder replacement can have an effect on overall efficiency of the device. Removal or extraction of spent tools and tool holder can be particularly time consuming if the removable part is bonded or cold-welded to its supporting structure as a result of repeated impacts during cutting or milling operation. Known systems for removing cutting tools, such as the system described in European Patent Office publication EP 1 045 075, rely on insertion of a wedge member into the tool holder so that the tool can be pushed from the tool holder by striking the wedge with a hammer or similar tool. Likewise, tool holders have traditionally been removable by striking a rear end of the tool holder with an extraction tool to push the tool holder form the drum or a base block mounted on the drum. More recently, however, tool holder extraction systems have been introduced that rely upon wedges acting against grooves formed in a surface of the tool holder. These systems, although effective, are subject to improvement.
For example, known wedge systems for cutting tool removal rely on a wedge member that is hammered upon by a service technician with the wedge extending generally perpendicularly from the tool holder. This arrangement requires the technician to have adequate space to access the wedge and may thus require the technician to work on the tool extraction with the tool and tool holder low to the ground to provide adequate overhead space. Known wedge systems for tool holder remover typically rely upon two separate wedges that are individually driven into extraction grooves formed in a surface of the tool holder. These independent wedges are stuck alternately by the service technician to cause the tool holder to work its way from the drum or base block. Because the wedges are loose and independent, the technician must control each wedge carefully. One solution to this problem is to provide a tool having a pair of wedge pieced fixed to together, but such a tool requires precise alignment of the grooves and the tool.
This disclosure is directed toward overcoming one or more of the problems described above.